New constructive counterexamples to additivity of minimum output Rényi p-entropy of quantum channels

Abstract

In this paper, we present new families of quantum channels for which corresponding minimum output Rényi p-entropy is not additive. Our manuscript is motivated by the results of Grudka et al., J. Phys. A: Math. Theor. 43 425304 and we focus on channels characterized by both extensions and subspaces of the antisymmetric subspace in C^d⊗C^d, which exhibit additivity breaking for p>2.